The present invention generally concerns an improved radon detection package, and methods of making and using same.
Radon is a heavy radioactive gaseous element, which exists naturally in the environment, and often resides as ground gas in the soil. Radon levels vary considerably at different sites, and over time on any given site. Because naturally-existing radon levels are now known to sometimes be high enough to cause health concerns, products have fairly recently been introduced to aid in the detection of radon at a particular location. In general, radon detection aides have taken the form of a sealable package of radon absorption material, commonly such as activated carbon (e.g. charcoal), which is situated in an area to be tested and exposed to the ambient air for a testing period. The radon absorption material is later analyzed, such as with spectroscopy or the like, to determine the level of radon, if any, absorbed thereby. In this manner, a given test site, such as a room or basement of a house or building, may be tested for the presence and/or level of radon therein.
Because various factors give rise to variations in naturally-existing radon levels at any one time, such as atmospheric pressure changes (eg. low pressure centers, such as storms, may draw higher levels of ground gas from the soil), typical prior art packages have been used for testing periods of from 6 to 72 hours, and preferably from about two to about three days. Some suggested testing periods extend for seven days. The thought behind a testing period of several days is that an average level of radon for a given test area is determined since radon levels may change radically in the course of only several hours, such average level thus reflecting a truer idea of radon levels at the test site.
While prior art radon testing packages have heretofore been thought to obtain at least satisfactory results with testing periods extending for several days, the present invention recognizes a problem of radon retention over such extended testing periods. In particular, the present invention recognizes that, while radon typically is rapidly taken on or absorbed by commonly used radon absorption materials (eg. activated carbon), the absorbed radon is subsequently driven off from the activated carbon by the absorption of moisture as the test proceeds. It has in fact been determined that, in general, the greater the ambient moisture conditions during a given testing period at the test site, the greater extent to which absorbed radon is driven off from the testing package as the test proceeds beyond a certain time (generally about six hours).
Since the above-noted radon retention problem is more prevalent with higher moisture conditions, testing during summer months is typically more problematic than during winter months since moisture averages can run about 50% higher during the summer months than the winter months.
One typical conventional radon testing package comprises a paper pouch forming a single chamber for receipt of activated carbon or other radon absorbing material. Before and after the testing period, such pouch is retained in a sealed envelope, container, or other like member for shielding the pouch from ambient air and radon. During the testing period, the pouch is vertically suspended or otherwise placed in the testing area, during which time it is fully exposed on all sides to ambient air and radon. Radon is absorbed directly through the paper pouch into the activated carbon. Once the test is complete, and the pouch is returned to a processing location in its shielded container, the activated carbon may be subjected to spectroscopic analysis to determine the amount or level of radon absorbed therein, which level is related to the amount of radon present at the testing site during the testing period.
Obviously, if there is a problem with adequate radon retention by the absorption material, for whatever reasons, the resulting test data will be flawed to the extent that it supposedly indicates a level of radon at the testing site. In particular, if during the testing period radon initially absorbed is subsequently driven off to some degree by the absorption of moisture (as applicant has determined is typically the case with the above-mentioned conventional type of package), subsequent spectroscopic analysis can lead to a false indication of no radon level problem at the test site. Accordingly, it is one object of the present invention to recognize and overcome such disadvantage of the above-mentioned typical conventional radon testing package and testing methodology.
Table 1, infra, provides some data comparing radon retention performance of such conventional package and the improved radon detection package and related methodology disclosed herewith.
In recognition of the foregoing radon retention problem, it is a general object of the present invention to provide an improved radon detection package, particularly having improved radon retention characteristics. It is a more particular object to provide a radon detection package for use in radon testing which generally absorbs and subsequently retains greater levels of radon while reducing the degree of moisture absorbed and retained.
It is another general object of the present invention to provide an improved radon detection package, and testing methodology utilizing same which provides improved counting statistics for spectroscopic analysis. It is a further object of this invention to enable elevated levels of radon retention for improved detection in spectroscopic analysis, which enables more efficient processing of multiple packages by providing relatively higher levels of radon in each such package.
It is yet another object of the present invention to provide an improved radon detection package which has balanced absorption and retention characteristics to permit a practical testing period of about two to about seven days, by having absorbed and subsequently retained during such a testing period an adequate and desireable level of radon for detection purposes without collecting and retaining a deleterious amount of moisture. It is a more particular object of this invention in providing such a package to provide for a controlled amount of air and radon to have access to a pouch or similar container of radon absorption material during a testing period.
It is yet a further object of the present invention to provide such an improved radon detection package which conveniently converts into a self-mailer for return of same by the user to a centralized processing station.
Further objects of the present invention are directed to providing such an improved radon detection package which may be manufactured in accordance with an exemplary preferred method disclosed herewith, and which may likewise be efficiently used for capturing radon with an exemplary method disclosed herewith.
Various constructions and methods may be practiced in accordance with different combinations of features and steps of the present invention disclosed herewith. One exemplary construction is directed to a package for use in testing for the presence of radon in a given area, such package comprising: pouch means for holding absorption material capable of trapping radon gas particles, such pouch means being preferably adapted for support thereof in a substantially vertical orientation in a given area for absorbing radon present in such area; hood means for substantially surrounding the pouch means with a radon-barrier material during testing of a given area, while also providing access to the pouch means via an opening preferably defined generally on the lower side of the hood means whenever the pouch means is situated in a vertical orientation, the opening being adapted for selected sealing thereof after testing of a given area so as to thereafter prevent radon from entering into or escaping from the hood means; and air flow means for maintaining the opening generally open during testing to permit ambient air and radon to have access generally to the bottom and along at least one side of the pouch means during such testing, and for permitting the selected sealing of the opening thereafter.
Yet another particular exemplary embodiment in accordance with the present invention includes a testing package for radon detection, having improved retention of radon and resistance to moisture absorption over the course of a testing period, such package comprising: a generally flat outer pack of radon barrier material, configured so as to define a chamber therewithin and a closable entrance located at one end of the pack for providing selected access to such chamber, such pack being adapted for support thereof in an area to be tested for radon, in a predetermined orientation with the chamber entrance selectively held open to permit the introduction of radon from the given testing area into the chamber; and a pouch formed of material which is porous to radon, the pouch being filled with radon trapping material and situated inside the chamber; whereby any radon present in a given area may be conducted into the chamber through the entrance thereto and trapped within the radon trapping material therein during a testing period, and thereafter retained within the pack by closing the entrance thereof for subsequent detection of any such radon.
While various method steps are disclosed herewith in connection with producing an improved radon detection package in accordance with this invention, one exemplary method, in accordance with this invention, of making an improved radon detection package comprises the steps of: placing a folded sheet of first material between two opposing sheets of a second material; commonly sealing side edges of the sheets so that the two opposing sheets have opposite open ends with a folded edge of the folded sheet being situated adjacent one of the open ends of the two opposing sheets, such folded sheet of first material thereby forming a pouch secured between the two opposing sheets of second material, an open end of which pouch is situated adjacent the other of the open ends of the two opposing sheets; filling the pouch through the open end thereof with radon absorbing material; and commonly sealing the pouch open end and the other open end of the two opposing sheets, whereby such filled pouch is thereby sealed, and is substantially enclosed between the two opposing sheets except for the remaining such one open end of the two opposing sheets; further comprising providing the first material permeable to radon to permit same to enter such filled pouch and be absorbed therein, and providing the second material impermeable to radon so that the pouch can be substantially surrounded with a hood-like structure during a radon testing period and thereafter substantially sealed by closing the one open end of the two opposing sheets.
While various method steps are disclosed herewith in connection with using an improved radon detection package in accordance with ths invention, one exemplary such method of capturing radon present in a given area, in accordance with the present invention, for subsequent detection thereof comprises the steps of: providing a testing package having an internal pouch of activated carbon for absorbing radon, and having an outside hood-like structure for substantially surrounding the pouch while defining at least one sealable opening for providing access thereto, such pouch being comprised of radon-permeable material and such hood-like structure being comprised of radon-barrier material; exposing the pouch for a finite testing period within a given area to be tested for the presence of radon; and sealing the sealable opening at the end of the finite testing period; whereby the activated carbon exposed to radon present in the given area during such testing period is sealed for subsequent detection of radon absorbed therein.
Still further in accordance with this invention, another and preferred exemplary method of capturing and retaining radon present at a selected testing site for subsequent detection thereof comprises the steps of: providing a pouch of radon absorption material; during a testing period, supporting the pouch at a selected testing site within a hood-like structure of radon impermeable material, the structure substantially surrounding the pouch and defining a generally downwardly-directed opening for providing access of ambient air and radon to the pouch; during such testing period, establishing a channel within the hood-like structure, connecting with the structure opening and extending along such structure, and in which the pouch is supported, whereby controlled exposure of the pouch to the ambient air and radon is obtained; and at the close of such testing period, sealing the pouch until time for detection of the radon.
While exemplary constructions and methods in accordance with this invention have been particularly set forth above, those of ordinary skill in the art will appreciate changes to same which may be practiced without departing from the broader teachings of this invention, all of which such variations are intended to come within the scope of the present invention by virtue of present reference thereto.